What does infant perception tell us about theories of perception?

The article begins with a summary of eight well-substantiated conclusions drawn from research on perception in infants that have implications for theories of perception. The following section examines several traditional and modern theories of perception in the light of these conclusions. Finally, some "big issues" that have divided perceptual and cognitive theories are discussed, with the suggestion that research on infants can help reconcile the divided camps. Research on perception in young infants not only flourishes but also presents a challenge to all theories of perception.     

What does the occluding contour tell us about solid shape?

A new theorem is discussed that relates the apparent curvature of the occluding contour of a visual shape to the intrinsic curvature of the surface and the radial curvature. This theorem allows the formulation of general laws for the apparent curvature, independent of viewing distance and regardless of the fact that the rim (the boundary between the visible and invisible parts of the object) is a general, thus twisted, space curve. Consequently convexities, concavities, or inflextions of contours in the retinal image allow the observer to draw inferences about local surface geometry with certainty. These results appear to be counterintuitive, witness to the treatment of the problem by recent authors. It is demonstrated how well-known examples, used to show how concavities and convexities of the contour have no obvious relation to solid shape, are actually good illustrations of the fact that convexities are due to local ovoid shapes, concavities to local saddle shapes.     

What can autism and dyslexia tell us about intelligence?

This paper argues that understanding developmental disorders requires developing theories and models that explicitly represent the role of general intelligence in the cognitive phenotype of the disorder. In the case of autism it is argued that the low-IQ scores of people with autism are not likely to be due to a deficit in the cognitive process that is arguably the major cause of mental retardation - namely, speed of processing - but rather low IQ reflects the pervasive and cascading effects of the deficit in the information-processing module that causes autism. In the case of dyslexia, two radically different models of reading disorder (ability = disability and a modular deficit model) are likely to be influenced by the effect of general intelligence on reading performance in ways that will remain unclear without an explicit model of how general intelligence influences reading.     

What does the MTA study tell us about effective psychosocial treatment for ADHD?

Discussed the initial findings from the recently published, National Institute of Mental Health-sponsored Multimodal Treatment Study (MTA) of attention deficit hyperactivity disorder (ADHD). These findings can be summarized as follows: Medical management alone was found to be significantly more effective for the core symptoms of ADHD as compared to behavioral treatment alone and routine (community) care, and behavioral treatment did not significantly improve outcome when combined with medical treatment. In discussing these findings, it is important to be explicit about the research questions the study was and was not designed to answer. The MTA study provided useful information regarding the question, "Does a very intensive form of behavioral treatment deliver greater benefits than the less intensive forms of behavioral treatment investigated in prior studies?" but little insight on the question, "What type of treatment by what type of therapist is most effective in dealing with what specific problems among specific children with ADHD?" It is suggested that the clearest finding from the MTA study is that the effectiveness of psychosocial intervention for ADHD hinges on the degree to which a broad range of treatment ingredients are considered, carefully selected, matched, and tailored to the individual needs of each child with the disorder, and implemented and monitored over the long term.     

What do decision models tell us about information use?

This paper develops hypotheses about the implications of different types of decision for the utilization of different types of systematically produced information: data, research, and analysis. The engineering and enlightenment models found in the knowledge utilization literature prove inadequate for this purpose. We turn to three decision models—routine, incremental, and fundamental–and determine their implied demands for information. We also examine how information might be used in scanning procedures in anticipation of decision regime shifts. The results suggest that patterns of information should differ markedly in each decision context and indicate that there may be an inherent bias against the use of research in decision. Evert A. Lindquist, a doctoral candidate at the Graduate School of Public Policy, University of Calfornia at Berkeley, is completing a dissertation onPolicy Institutes in Canada: The Organization and Relevance of Public Inquiry and will join the faculty of the Department of Political Science at the University of Toronto this fall. Organizations, public policy, and the role of information in decision making are among his primary research interests.     

What does the nature of the stimuli tell us about the Global Precedence Effect?

The "Global Precedence Effect" (GPE) is a well-established phenomenon characterised by a global advantage (global response times that are faster than local response times) and an interference effect from global distractors during identification of local targets but not vice versa. In the present study, two experiments were carried out to examine how the GPE is affected by the meaningfulness of the stimuli. Using global/local compound stimuli based on either meaningful or meaningless stimuli, we found, on the one hand, that the global level was always processed faster than the local level, irrespective of the meaningfulness of the material. On the other hand, results show that the interference effect occurred only with meaningful stimuli. We propose that automatic identification of meaningful stimuli plays a role in the interference effect. These results suggest that the GPE involves both "sensory mechanisms" (responsible for the global advantage) and "cognitive mechanisms" (responsible for the interference effect).     

Release from Pl in running memory: What does this tell us about developmental STM?

Several theories consider the development of short-term memory (STM) in children to reflect the development of processing operations. This article reports an experiment that tested some of these theories, using a release from proactive interference (PI) procedure in conjunction with a running memory task, to track down age-related improvements in the processing of various kinds of information. Although evidence for the development of PI release with age appeared for two kinds of information, namely class of item and acoustic similarity, there was no evidence whatsoever for the existence of a relationship between STM performance and PI release. It was concluded that the development of STM on the one hand, and of the capacity to process item or acoustic information on the other, proceed independently of each other. The discussion deals with the apparent conflict between this conclusion and the theoretical positions.     

What do our intuitions about the experience machine really tell us about hedonism?

Robert Nozick’s experience machine thought experiment is often considered a decisive refutation of hedonism. I argue that the conclusions we draw from Nozick’s thought experiment ought to be informed by considerations concerning the operation of our intuitions about value. First, I argue that, in order to show that practical hedonistic reasons are not causing our negative reaction to the experience machine, we must not merely stipulate their irrelevance (since our intuitions are not always responsive to stipulation) but fill in the concrete details that would make them irrelevant. If we do this, we may see our feelings about the experience machine becoming less negative. Second, I argue that, even if our feelings about the experience machine do not perfectly track hedonistic reasons, there are various reasons to doubt the reliability of our anti-hedonistic intuitions. And finally, I argue that, since in the actual world seeing certain things besides pleasure as ends in themselves may best serve hedonistic ends, hedonism may justify our taking these other things to be intrinsically valuable, thus again making the existence of our seemingly anti-hedonistic intuitions far from straightforward evidence for the falsity of hedonism.     

Categorization and action: What about object consistence?

Categorization studies have focused on the importance of a variety of perceptual properties (shape, size, weight). The present study explored whether the softness or hardness of an object might influence the way we categorize and consider category members. Of additional interest was whether information on consistence is automatically activated and whether it is modulated by the kind of task and of response modality. Three experiments demonstrated that information on consistence is automatically activated, and it helps us to distinguish between artefacts and natural objects. Interestingly, the results are in agreement with the simulation hypothesis; namely, when we consider artefacts, we simulate using them and information on their consistence is activated; this simulation is modulated by the task. The way we differently process artefacts and natural objects across the experiments confirms the simulation hypothesis and our sensitivity to the response modality.     

What can regular and timely student feedback tell us about the teaching and learning processes?

Most studies on the evaluation of teaching focus on the input (teacher traits) or the output (student-generated products) of the teaching and learning processes. This article is based on a case study that examines the three components of teaching and learning: input, output and process. It presents a framework for collecting quantitative and qualitative data on the quality of instruction, assessment and feedback, and learning environment in college composition courses to complement the feedback provided by the end-of-course student evaluations of teaching for the purpose of monitoring, guiding, and improving instruction.     

Reflections on the study of infant perception and cognition: what does Morgan's Canon really tell us to do?

This commentary on Needham's (2001, this issue) work focuses on the types of evidence needed to make inferences concerning infant cognition. It is helpful to consider the history of the positions that have been held by scientists who have tried to explain the cognitive abilities of animals, deemed to be so very different from adult humans, and in that regard, similar to infants. The justification of inference is not a matter of personal taste or the application of a rigid doctrine. Rather, the study of infant cognition requires a high level of creativity in the creation and testing of alternative explanations. By understanding lessons from our past, current researchers should be better able to conduct their studies and draw appropriate conclusions.     

What can performance tell us about learning? Explicating a troubled concept

The notion of “performance7rdquo; has a central place in the contemporary discourse of learning and competence. The notion is used to translate abstract ideas and ideals of lifelong learning, organizational learning, learning society, etc., into practical measures. Changes in performance provide the identifiable measures that learning has taken place, evidence of enhanced competency/capability. Different versions of the learning and competency/capability agenda may place different emphases upon the extent to which such performance changes may be predetermined or are essentially emergent, but the assumption remains that performance provides the basis for attribution that learning has (or has not) taken place. This article takes issue with the conventional notion of “performance” as unequivocally observable. Drawing upon traditional philosophical distinctions between behaviour and action, and interpretative, constructionist, situational, and relational traditions within the social sciences, the nature of performance is subjected to theoretical analysis. It is argued that performance cannot be taken as transparent evidence of learning. Rather the attribution of performance is itself the outcome of situated acts of interpretation, essentially contestable and negotiated, subject to reinterpretation and renegotiation. The key social processes by which such interpretation is accomplished will be shown to implicate issues of identity (and identity formation) and social practice (and its discursive production). The potential fruitfulness of the identity-practice model will be illustrated by applying it to the issue of graduate “employability”, in order to address problems with the conventional “skills” approach.     

What can subjective forgetting tell us about memory for childhood trauma?

In the present study, we examined the prevalence and predictors of subjective forgetting (i.e., self-reported amnesia) of child sexual abuse (CSA). Adults who, as children, were involved as victims in legal prosecutions were questioned about their CSA experiences, which had been documented in the 1980s, and about lost and recovered memory of those experiences. Males and individuals who experienced more severe abuse were more likely to report forgetting. The majority of individuals attributed their forgetting to active attempts to avoid thinking about the abuse. In contrast, when predictors of subjective forgetting were used to predict objective memory of abuse, more severe abuse and more extended legal involvement were associated with fewer memory errors. The differences between subjective and objective memory underscore the risks of using subjective measures to assess lost memory of abuse.